Cooling jacket, especially for electrical machines and method for the manufacture thereof

ABSTRACT

The invention relates to cooling jackets and/or heat exchangers, which are to be placed in contact with solid products that are to be cooled, especially with electrical machines with a rotor rotating inside or outside a stator, or in contact with reactors or containers. Said jackets and/or heat exchangers have an inner wall and an outer wall which form the boundary of a flow cavity that is provided with inlet and outlet means for a cooling medium and conducting means in order to form and/or limit at least one flow path for the cooling medium between the inner wall and the outer wall from the inlet means to the outlet means. According to the invention, opposing individual flat places or flat sections of the inner wall and the outer wall are in contact with one another within the confines of said walls and passages for the cooling medium remain between the contacting flat places of flat sections. One or more elevations and depressions alternate on one or more external sides or an outer casing of the inner or outer wall, wherein adjoining flat places or flat sections are permanently connected over individual joints and/or elongated joint sections.

The invention relates to a cooling jacket and/or heat exchanger which is to be placed in contact with objects of solid form (solid products) to be cooled, such as, for example, electrical machines, reactors or containers. The cooling jacket/heat exchanger presents an inner and outer wall, delimiting between themselves a flow cavity. The latter is provided with inlet and outlet means for a coolant and with conducting means for the formation and/or delimitation of at least one flow path for the coolant, where the flow path extends between the inner and outer wall from the inlet means to the outlet means. The inner wall presents a smooth or largely smoothened external side, which is in close fitting contact with the solid product or the object to be cooled. With regard to electrical machines with external rotor and internal stator in particular, the reversed arrangement system also falls within the scope of the invention; i.e., the outer wall of the cooling jacket possesses a smooth upper surface or outer surface allowing a close fitting contact with the object of solid form to be cooled (solid products).

Casings for aggregates of solid form, through which cooling coils or cooling ducts pass, can be manufactured only at great expense from stainless chromium nickel steel. The manufacture of the casing is expensive, and the solid body aggregates, for example, electromotors, must be shrink fitted in such a casing. The introduction of cooling hoses or pipes is time consuming. In addition, the hoses or pipes must be provided with appropriate connections for the fluid feed, where, as a general rule, hoses or screw connections with seals are used. Both solutions may lose their sealing property due to aging. In many cases, the repair of such a cooling system, when damaged or leaking, can be carried out only with difficulty or is no longer possible.

Electromotors in which the stator plate is held by a double walled cooling jacket with flow ducts for coolant in the interior are known, for example, from the manufacturer “PHASE MOTION CONTROL,” 16141 Genoa, Italy, under the type designation “Squid Torque Motor.” An internal casing jacket is shrink fitted directly on the stator plate packet, and provided with separating webs that protrude radially outward, and run in a helical line. Correspondingly, the cooling ducts that run in between also run in a helical line. Such an external casing jacket covers the cooling channels towards the outside.

U.S. Pat. No. 3,075,103 describes a cooling ring through which fluid flows, and which is used for encapsulated electromotors. The stator is enclosed by a pressurized container. An integrated heat exchanger located therein is formed with parallel grooves which are incorporated in the interior surface of the pressurized container. The open side of the grooves is covered by a steel cylinder which is concentric with respect to the motor shaft. Cooling copper windings which are turned radially inward are in contact with the external side of the steel cylinder, and in thermal contact with the stator windings. For this purpose, the surface—which is turned radially inward—of the cylinder inner shell is in the shape of a regular circular cylinder. In the same way, the pressurized container presents an outer casing with smooth surface.

U.S. Pat. No. 3,009,072 describes fluid cooled motors, which are surrounded by a cooling jacket. The purpose is to produce, between the electroplate of the motor and/or its casing and the cooling jacket as intense a heat contact as possible, while using a compact construction. For this purpose, in the stator or in the motor shaft or in the rotor and/or in an external casing jacket surrounding the former, groove channels are formed. Between the stator/rotor electrical sheet, on the one hand, and the external casing jacket, on the other hand, as a lining, a sandwich arrangement with two concentric layers or coats is inserted. The sandwich arrangement is thus located between the exterior casing jacket, on the one hand, and the electrical sheet of the motor, on the other hand. In an additional manufacturing step, a pressure medium is injected between the two layers of the sandwich arrangement, resulting in the two sandwich layers being pressed against the given surfaces of the motor electrical sheet and of the external casing jacket surrounding the motor electrical sheet. In the process, groove channels which are worked into the electrical sheet and/or the inner wall of the exterior casing jacket, press against the given layer or coat of the sandwich arrangement, forming a copy. As a result, passages for cooling fluid form between the two layers of the now broadened sandwich arrangement. However, the disadvantage is that after the leak of the pressurized medium out of the sandwich structure, the latter can easily undergo deformation again about an elastic deformation part and in the process it can be raised from the electrical sheet and/or the casing, resulting in a critical increase in the heat transition resistance, and in a lowering of the effectiveness of the heat removal. In addition, the manufacturing cost is increased, due to the formation of groove channels in the electrica sheet or in the casing inner wall.

WO 00/54 991 describes an arrangement with a cover through which a current flows, and with an electrical wheel motor within a wheel hub, which carries a tire. Cooling air is led through the middle of the electrical wheel guided, and deflected by the cover. A cover ring is connected to the wheel motor edge by means of a clamping element.

For additional technical background literature, reference is made to DE 1 231 797, DE 1 136 412, DE 961 186 and DE 28 36 903.

In contrast, the invention is based on the problem of simplifying the method of manufacturing a double walled cooling jacket of the type mentioned in the preamble. For the solution, reference is made to the cooling jacket or heat exchanger indicated in Claim 1. A method of manufacture of such a cooling jacket or heat exchanger is given in Claim 22. Claim 39 indicates a cooling arrangement with an electrical machine and with a cooling jacket or heat exchanger according to the invention. Advantageous optional embodiments of the invention can be obtained in the dependent claims.

According to the invention, between the inner and outer wall and within their edges, only selected permanent joints or joint lines or sections are formed, with space left between the latter to produce coolant flow passages in the flow cavity. This results in a nonsmooth external side of the outer wall facing the outside environment. Elevations which are formed by the flow passages alternate with recesses which coincide with the joints or joint sections. Thus, the outer casing of the outer wall runs, for example, in an uneven or wavy manner with respect to a base plane or a base circle or cylinder of the cooling jacket over the alternating elevations and recesses. As a result, the external surface of the cooling jacket or heat exchanger, which is in contact with the external environment, is considerably enlarged, which improves the effectiveness of the heat transfer. However, the most important relevant factor is the cooling of the smooth mantel surface from inside.

In the cooling arrangement according to the invention with an electric machine and a cooling jacket/heat exchanger, one achieves the advantage of being able to cool stators without casing or fully plated stators, without having to set up a bearing casing or cooling hoses or pipes in the stator for that purpose. Because, in the invention, the cooling jacket does not represent a mechanically bearing component of the motor construction, there is complete functional separation between the mechanical bearing structure and the cooling. As a result, the wall thickness of the cooling jacket or of its inner and outer wall, on the one hand, can be chosen to be very thin, which makes even the use of high value materials, for example, stainless chromium nickel steel, economical. When using this material especially one can use advantageous thicknesses of 0.3-2.0 mm, for example, 0.8 mm for the inner and outer walls. On the other hand, if no fluid cooling is needed, the entire cooling system can be omitted by simply omitting or removing the cooling jacket.

The problem, which was explained above in relation to the discussed state of the art, namely, the lifting of the double walled cooling jacket from the groove channels that have been produced in the delimitation surfaces, when a release of the deformation pressure occurs consecutive to the application by pressing, is prevented in a targeted manner by the invention by the fact that the formation or inflation of the duct structure occurs on a separate device. The resulting pillow-like structure is clamped only after the release of the deformation pressure onto the object to be cooled, or pressed permanently against the latter in another way. As a result, a direct contact between the wall of the duct system of the cooling jacket and the object to be cooled is ensured.

In the context of the invention, the joints and/or joint sections are produced by fastening respectively welding or soldering. Additional sealing measures are provided for screwing and/or riveting. Fastening or welding is advantageous to the extent that, for this purpose, one can use welding robots which can be programmed appropriately ahead of time for the application of welding or fastening locations. This programming can be implemented, for example, in such a way that the result is an arrangement of the joints and/or joint sections resulting in meandering flow paths of the coolant, optionally with turbulence. Furthermore, based on the invention, one obtains the advantageous embodiment where the recesses and/or flow conducting means can be produced using a simple construction with joints and/or joint sections.

To allow the cooling jacket to be able to be applied with its inner wall with close fitting contacts against the solid to be cooled, a shape adaptation to the solid is needed, which can be achieved, for example, by means of a deformation device. In this connection, it is advantageous to form mounting and/or fixation means on or in the outer and/or inner wall of the cooling jacket, to allow the attachment to the deformation device.

To improve the heat transfer, the interior of cooling jacket/heat exchanger and/or the outer casing or side of the solid object to be cooled can be provided with a coating which improves the heat transfer. This coating consists preferably of a viscoelastic polymer which is applied, for example, on the inner side of the cooling jacket, and which, after the mounting of the cooling jacket, compensates for slightly uneven parts of both the external surface of the product to be cooled and also the internal surface of the cooling jacket. Such coatings can be produced with commercially available products, such as, for example, ISO-PUR K 750/HDI23-2000 (a transparent, unfilled, cold hardened 2-component polyurethane casting resin), which is available from the company ISO-ELEKTRA GmbH, Im Mühlenfeld 5, 31008 Elze. An alternative PU casting compound can be produced with the product Rhenatech® PU 4714 FR with the hardener PU4900 available from the company Beckelectrical insulation GmbH, Goβmannstraβe 105, 20539 Hamburg. Such polymer viscoelastic coatings intended to improve the heat transfer are applied advantageously before the mounting of the cooling jacket on the external surface of the solid product to be cooled and/or the inner side of the cooling jacket. The use of heat conducting pastes or adhesives in itself is already known. The disadvantages here are the handling during the mounting and the risk of soiling, particularly if the product to be cooled together with a cooling jacket is to be lacquered at the end. An additional advantage of the embodiment comprising the polymer coating is that it allows, in the case of possible damage, simply removing an already mounted cooling jacket/heat exchanger from the motor or from another product to be cooled, and replacing it.

To compensate for uneven places, interstices, open places or the like between the external side of the cooling jacket inner wall of the facing external side of the product to be cooled, a complementary alternative possibility exists where a casting compound or impregnating resin which is used anyway for the stator plate or the stator windings is also used for the mentioned. An additional coating material for the mentioned purposes could then be omitted. As long as the casting compound for the stator or its windings or for another similar product has not yet hardened completely, the cooling jacket can be mounted advantageously in the context of the invention. Then, there is automatic shape adaptation of the casting compound to still existing uneven places, free interstices, etc., between the facing external sides of the cooling jacket and the product to be cooled. As long as the casting compound and/or the impregnating resin used commonly for electrical sheets or windings of stators has not hardened yet, it can spread out between the facing application surfaces of the cooling jacket and the product to be cooled, and, as a result, close any heat transfer gaps that may still be present. When using the casting compound which is used anyway for the product to be cooled, such as, a motor stator, the additional work step required for that purpose—namely, the application of a polymer viscoelastic intermediate coating—can be omitted in the above-explained invention embodiment. Uneven places on the periphery of the product to be cooled, such as, for example, an electromotor and/or on the external side of the inner wall of the cooling jacket, can also be filled out or compensated with casting compound.

An invention embodiment is also conceivable where the cooling jacket is mounted prior to the above-discussed impregnation process. As a result, the impregnating resin can penetrate between the cooling object, for example, a stator, and the cooling jacket. The penetration may optionally be improved further if the cooling jacket, in the interior of each circular weld for connecting the interior and exterior plate, presents a bore through which resin can also penetrate to the jacket surface itself during the impregnation, or air can escape.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the elevations and recesses present a convex or concave curvature.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the joints and/or joint sections (10) are implemented by fastening respectively welding, soldering, gluing, folding, clinching, screwing and/or riveting.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the joints and/or joint sections are arranged in the area of the recesses of the given external side of the inner or outer wall.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the recesses and/or flow conducting means are implemented with the joints and/or joint sections.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger which presents a cylindrical and/or longitudinal and/or rotation symmetric base form—in an alignment that is parallel or viewed along the cylinder, longitudinal or symmetry axis—on the external surface or side of the inner or outer wall, where each elevation or recess is delimited on all sides in each case from recesses or elevations that are outside the alignment.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the flow guidance means with the joints and/or joint sections and/or joints or joint sections are implemented between the inner and outer wall.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, an arrangement of the joint places and/or joint section exists which is such that the flow path(s) of the coolant have a meandering course and/or a turbulent course.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger which presents a cylindrical and/or longitudinal and/or rotation symmetrical base form, several longitudinal joint sections of the inner and outer wall are offset, in a peripheral direction about the cylinder, longitudinal and/or symmetry axis, alternatingly more toward one edge and more to a facing edge.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger which presents a cylindrical and/or longitudinal and/or rotation symmetric base form, several joints and/or joint sections are arranged with mutual offset in a peripheral direction about the cylinder, longitudinal and/or symmetry axis and/or in a direction parallel to the cylinder, longitudinal and/or symmetry axis.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the joints and/or joint sections are arranged with regular structure and/or equal separations from each other.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, mounting and/or fixation means are provided on or in the external and/or inner wall for the attachment to a deformation device.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, the inner and/or outer walls are implemented with plate parts having a thickness of 0.3-2.00 mm, for example, 0.8 mm.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger which presents a hollow cylindrical base shape, where the cylinder peripheral jacket presents an axis-parallel butt seam, or joint, which is formed by edges of the inner and outer wall, which edges face the peripheral direction, the facing edges are held together or immediately opposite each other by spring clamps, claw springs or other elastic clamping means and/or welding locations.

To ensure, in the case of the cooling jacket and/or heat exchanger, an effective heat exchange between the contact side assigned to the object to be cooled, and the outside environment, the outer and inner wall are formed with a smooth or largely smoothened exterior side for the close fitting contact with the solid product.

In the above-mentioned embodiments of the first variant of the invention, a separate work step for the fixation of a deformation device is necessary. Furthermore, the cooling jacket so obtained must also be fixed by appropriate clamping means on the motor or other object to be cooled. Here, a strong clamping force in the peripheral direction is necessary to ensure a sufficient application pressure of the cooling jacket around the object to cool.

As a cost saving measure, thin plates made, for example, of tenitic steel, are used for the cooling mantel or its double walled structure, which, however, results in a certain sensitivity of the cooling jacket with respect to mechanical damage from outside. As a correction, the following variants of the invention are used.

After the plate sandwich representing the cooling jacket has been bent after its welding to a cylinder jacket, it is provided with connectors which are welded preferably in the form of threaded flanges directly on the cover plate of the cooling jacket or plate sandwich. Now, a second plate cylinder is manufactured as cover jacket, which is made from normal steel plate to save cost. This jacket is designed with a thicker wall than the individual plates of the cooling jacket. If the thickness of the individual plates is 0.8 millimeter, for example, the thickness of the cover jacket is, for example, 2.5 millimeter or more. This cover jacket is provided with bores or other perforations through which the inlet/outlet connection flange or other connection elements of the cooling jacket can protrude later. Furthermore, the cover jacket is welded to a cylinder, by means of a longitudinal or a helical seam, depending on the winding of the cylinder. The cover jacket is given dimensions such that the cooling jacket fits with only little tolerance in its cavity. In a following manufacturing step, the cooling jacket is shifted into the cover jacket respectively its cavity. Because the cooling jacket itself is not yet welded to the cylinder, the threaded flange or other connection elements can be inserted, with appropriate placement, by elastic deformation of the cooling jacket, during the insertion, from inside through the prepared bores of the cover jacket.

For the mounting of the cooling jacket on the motor, the two coaxially premounted jackets are shifted axially onto the cylindrical motor section to be cooled. Subsequently, the channel structure is expanded by internal high-pressure deformation with water or oil. In the process, a much higher pressure is now necessary than in the above-described first variant of the invention with optional improvements, at which the cooling jacket alone is fixed and pressed onto a deformation device. As a result of the higher pressure to be used in the second variant of the invention, the thicker plate of the cover jacket is also deformed. In contrast to the case of the cooling jacket, where the duct structure is formed, the cover jacket is expanded predominantly in the peripheral direction, elastically or elastically-plastically depending on the interior pressure. When reducing the pressure, the existing very high preliminary tension of the cover jacket leads to a large radial force component directed inward. Because the duct pattern of the cooling jacket represents a structure with relatively high spatial frequency with material parts in a radial direction, the cooling jacket in radial direction with flat force introduction is sufficiently rigid so that a large part of the preliminary tension in the cover jacket is maintained, and radial components of said tension are active as a contact pressing force for the cooling jacket, to press the latter on the motor with reduction of the heat transfer resistance. In comparison to the application by pressing the cooling jacket alone on a deformation device according to the first variant of the invention, in the second variant of the invention, greater contact surfaces on the motor are generated due to the higher potential pressure during application by pressing with the cover jacket. These surfaces adapt completely to any unevenness of the motor outer casing, in any case to any unevenness that does not exceed a certain spatial frequency.

To improve the heat transfer, the cooling jacket or the motor surface can again be provided here, as in the first variant of the invention, prior to the mounting, with a coating which improves the heat transfer, and which then also compensates for small uneven places occurring at higher spatial frequency.

The second invention variant is characterized particularly by the process of pressing the structure that represents the cooling jacket directly on the object to be cooled, for example, a stator of an electromotor, using the cover jacket, to produce in this way a transversely pressed composite made of a cover jacket, a cooling jacket, and motor or other object to be cooled (reactor, vessel, container). One advantage is that, due to the application by pressing, a symmetric cushion or duct structure forms under the cover jacket. As a result, the local deformation in the area of the joints or joint sections, for example, of the welding seam penetration, is smaller. In addition, due to the radial pressure on the cooling jacket, compressive prestressing is generated in the welding seams that delimit the meander or cushion structure of the cooling jacket. Similarly, the method according to the second variant of the invention resembles in this regard the method of autofrettage, where, by controlled overextension using an internal pressure, compressive prestressing is generated. As a result, in comparison to the composite according to the first variant of the invention, which is pressed on separately and clamped around the motor, this composite possesses a durability that is increased by several orders of magnitude, providing even permanent resistance to swelling and/or pulsing pressure loads, which may occur in the cooling system if the system pressure changes often.

According to an optional invention embodiment, in the case of the cooling jacket and/or heat exchanger, both the inner wall and also the outer wall are designed with several alternating elevations and recesses on their given exterior sides. It is preferred for the elevations on the two sides to run symmetrically with respect to a middle line of the flow cavity, which line connects the joint places or joint sections.

According to an optional invention embodiment, a cover jacket thus covers and/or clamps around the cooling jacket and/or heat exchanger. The cover jacket is advantageously manufactured from steel plate and/or with a greater wall thickness than that of the inner or outer wall of the cooling jacket and/or heat exchanger.

According to an optional invention embodiment, the cooling jacket and/or heat exchanger is characterized by a structural integration with the cover jacket like a shrink wrap.

According to an optional embodiment variant, in the case of the cooling jacket or heat exchanger, the inlet and outlet means for the cooling medium are designed so they protrude through passages formed in the wall of the cover jacket.

According to an optional embodiment of the method according to the invention, for the formation of the solid composite, the two heat conducting plates are placed one above in the flat state respectively flatly, if possible congruently, and welded or otherwise connected at their edges.

According to an optional embodiment of the method according to the invention, for the formation of the solid composite, individual joints or joint sections are formed through its external side(s) and/or its outer casing, which results in mutually connecting facing inner sides of the inner and outer wall. The application of the individual joints or joint sections occurs advantageously by welding through the inner or outer wall. In the process, the joints or joint sections can be generated by point, circular and/or linear welding on the exterior side of the inner or outer wall.

According to an optional embodiment of the method according to the invention, the solid composite is adapted by deformation to the external contour(s) of a product to be cooled, in order to bring the cooling jacket or heat exchanger with the exterior side of its outer or inner wall into as close fitting a contact as possible with the product to be cooled.

According to an optional embodiment of the method according to the invention, for the deformation, the still flat plate composite is plastically deformed by means of a deformation device or a support body whose external contour corresponds to that of the product to be cooled. For the deformation, the still flat plate composite is advantageously bent to a cylindrical shape, or it is bent about a deformation core or a support body to a cylindrical shape, and connected to edges which in the process are facing and/or mutually impact. In particular, the plate composite can here be held with the external side of its outer or inner wall by fixation means in contact with the deformation device or the support body. Furthermore, the plate composite can be pressed for its fixation in the area of the welding or other joints on the support body or the deformation device. This application by pressing occurs particularly in the step b) indicated in Claim 22.

According to an optional embodiment of the method according to the invention, the internal high-pressure deformation is carried out by introducing a pressure medium, such as, for example, pressurized air or water between the inner and outer wall.

According to an optional embodiment of the method according to the invention, it is assumed that a deformation device is used for deforming the solid plate composite, where, to form the solid composite, through the latter's exterior side(s) and/or outer casing, individual joints or joint sections are introduced, whereby facing inner sides or interior flat parts of the inner and outer wall are connected to each other. During the phase of internal high-pressure deformation, holding-down devices are applied against the exterior side(s) or the outer casing of the outer wall in the area of the joints or joint sections and/or in the area of a peripheral seam or a welded peripheral edge, in order to hold the composite with the exterior side of its outer or inner wall in contact with the deformation device.

In an optional embodiment of the method according to the invention, the exterior side of the outer wall and inner wall is provided with a coating made of viscoelastic polymer, casting and/or impregnation resin and/or another coating substance that improves the heat transfer. Here, it is advantageous to use a cooling jacket and/or heat exchanger for a stator of an electrical machine without casing, where the machine is impregnated with casting and/or impregnation resin. The deformed plate composite is placed so that its inner wall is in contact with the stator, as long as the casting and/or impregnation resin has not yet completely hardened. It is advantageous for the stator to be impregnated in the area of its exterior edge or exterior periphery with casting and/or impregnation resin. In particular, before the impregnation, the cooling jacket is mounted on a solid product to be cooled.

According to an optional invention embodiment, in the case of the cooling arrangement, the inner wall is in heat conducting contact only with its protruding elevations with the outer casing or the outer wall of the stator.

According to an optional invention embodiment, in the case of the cooling arrangement, a coating with preferably plastically deformable heat conducting means is arranged between the exterior side of the inner wall and the exterior contour of the product to be cooled.

According to an optional invention embodiment, in the case of the cooling arrangement, where stator windings of the electrical machine are cast or thoroughly impregnated with a casting or impregnation compound, the casting or impregnation compound is also located between the exterior side or the concave outer casing of the inner wall and the outer wall of the stator or stator casing.

For both mentioned variants of the invention, electrical motors and generators, preferably without casing and with a fully plated design, as well as the containers or reactors to be cooled or heated, constitute suitable application fields. Torque motors in particular are suitable as cooling objects for the invention.

Additional details, characteristics, combinations of characteristics, effects, and advantages of the invention result from the following description of embodiment examples of the invention as well as from the drawings. The figures show:

FIG. 1, a schematic cross-sectional representation of the base structure of a cooling jacket according to the invention,

FIG. 2, a top view on a still flat cooling jacket according to the invention,

FIG. 3, a perspective representation of the cooling jacket which has already been partially deformed on an inner, pipe like deformation core,

FIG. 4, a perspective representation of the slightly wavy outer casing of the cooling jacket outer wall,

FIG. 5, the cooling jacket which had pulled and placed in the final position over an electromotor stator to be cooled, and

FIG. 6, the base structure of a second variant of the cooling jacket according to the invention in a cross-sectional representation corresponding to FIG. 1.

In FIG. 1, the cooling jacket according to the invention presents an inner wall 1 and an outer wall 2, which are configured so they are mutually concentric or coaxial, and connected via individual weld locations 3, for example, in the shape of a circle, at points or discrete places. Relative to the circle cylindrical course of the inner wall 1, the outer wall 2 extends in a wavy pattern or with contour partially offset radially towards the exterior, and it is tangent towards the interior to the outer casing of the inner wall 1 in the area of the welding locations 3. Thus, in the area of the welding locations 3, for the outer wall 2, valleys or recesses 4 result on its outer casing, where elevations 5 which are offset radially outward extend in a shape with convex curvature. As indicated with a dotted line in the axial front view of FIG. 1, the welding locations 3, 3 a are arranged with mutual offset both in the axis-parallel direction and also in the peripheral direction, so that, in the view according to FIG. 1, the welding locations 3, 3 a (which are in fact not visible and therefore only indicated with a broken line) located behind a (visible) elevation 5 form corresponding additional recesses 4 a. Overall, the recesses 4 alternate preferably regularly with the elevations 5 a, on the outer casing of the outer wall 2 along a common, axis-parallel alignment (extending vertically with respect to the plane of the drawing). Between an elevation 5 of the outer wall 2 and the inner wall 1, which elevation presents a convex curvature towards the outside, passages 6 remain for any cooling fluid or cooling medium flowing parallel to the axis. The latter medium thus flows parallel to the axis until it impacts, along the axis-parallel alignment, a (rear) connection or welding location 3 a, so that the cooling fluid stream is distributed in each case into stream passages 6 which run next to each other, and which delimit the (rear) welding location 3 a between them. As a result, interruptions are produced in the partially axis-parallel course of the coolant flow at the welding locations 3, 3 a, which results in meandering deflection courses and associated turbulence, and increases the cooling efficiency.

According to FIG. 2, for the formation of a double walled cooling jacket, two heat conducting plates 7, for example, flat plate parts, are placed flush and congruently in the flat state one above the other, which then form the inner and outer walls 1, 2 of the cooling jacket, after a subsequent manufacturing step. However, the upper and lower parts do not necessarily have to be congruent. In the top view of FIG. 2, only the upper plate of the heat conducting plates 7, which are preferably of the same design, is visible. On their edges 8, 8 a, 14 (according to the represented longitudinal-rectangular base form, four individual lateral edges) the two plate heat conducting plates 7 are welded circumferentially to each other. In addition, as a result of the welding process, the meandering flow duct structure for the cooling medium and/or an offset, spatially limited fastening of the sheet heat conducting plates 7 is produced.

According to the embodiment example of FIG. 2, in the longitudinal direction of the two superposed heat conducting plates 7, several rows I-V, with their axes approximately parallel to each other, are formed in each case with individual welding locations 3, 3 a which are arranged one after the other along the given alignment. These welding locations are, for example, circular in shape or present another round design, and they connect, in each case in places, the two mutually superposed heat conducting plates 7, so that corresponding joints form on their facing interior flat sides. After the cooling jacket (see FIG. 4) is in its final position, these joints oppose the coolant flow, forming an obstacle that cannot be overcome, and the coolant flow must in each case flow around them. The welding locations 3, 3 a of in each case two rows I, II; II, III . . . which are next to each other are arranged with mutual offset in the longitudinal direction, where the welding locations 3, 3 a of two rows II, IV which do not run directly next to each other face each other directly via a common, free transverse alignment 9 (running transversely to the plate longitudinal direction). As a result of the offset of the welding locations 3, 3 a in the longitudinal direction of the heat conducting plates 7 or in the final position state according to FIGS. 4 and 5 in the peripheral direction, many repeated deflections—and thus a meandering course of the coolant flow—are required from an inlet to an outlet.

Similar statements apply according to FIG. 2 also to the longitudinal welding sections or seams 10 which have a linear course in the depicted example. They start in each case from a welding location 3, 3 a, which locations, seen in the longitudinal direction of the heat conducting plates 7, are placed alternately in the area of one longitudinal lateral edge 8 and of the other facing longitudinal lateral edge 8 a, with mutual offset in the longitudinal plate direction. In other words, the longitudinal joint sections 10 are offset in the longitudinal direction (and thus in the final position state in the peripheral direction) alternately more toward one edge 8 and toward the other facing edge 8 a.

The length of the longitudinal joint sections 10 is chosen such that they pass—transversely to the longitudinal plate direction (axis-parallel in the final position state according to FIG. 4)—in each case through two rows I, II or IV, V of welding locations 3, 3 a which succeed each other in the longitudinal direction. In the process, the longitudinal welding sections 10 start in each case from the welding locations of a row I, V or alignment which are located closest to the two longitudinal lateral edges 8, 8 a. They extend in each case between two welding locations 3 which succeed each other directly in their given common row II, IV, where the given row or alignment II, IV is located closest to one of the outermost rows I, V. It is advantageous for the longitudinal welding sections 10 to terminate in the alignment of a middle row III with the welding locations 3 a.

According to FIG. 2 and its embodiment example, fixing bores 11 are also provided, which pass through the mutually superposed heat conducting plates. Like the welding locations 3, 3 a and the welding sections 10, the fixing bores 11 are in an arrangement with regular separations from each other, so that a regular and densely wavy structure can be produced for the outer casing of the outer wall. In series manufacture it can be particularly advantageous to use holding-down devices in addition to or instead of the fixing bores.

After the manufacture according to FIG. 2, the resulting plate sandwich is then bent to a cylinder jacket for a product 19 to be cooled, and, according to FIG. 3, fixed on a hollow cylindrical deformation core 13 by means of fixing screws 12 which present a design that is complementary to the fixing bores 11. According to FIG. 3, the two transverse edges 14 of the plate sandwich are fixed on the outer casing of the metal deformation core 13, by means of mounting welding locations 15, which can be removed again in a later manufacturing step. In series manufacture it can be advantageous to use holding-down devices in addition to or instead of the mounting welding locations. A pressure line 16, for example, an inflation pipe, passes through the outer wall 2 which alone is visible in FIG. 2, so that a pressurized fluid, for example, pressurized air, can be introduced into the flow cavity 17 (which is not yet fully formed according to FIG. 3) (see FIG. 1).

According to FIG. 4, the area between the two heat conducting plates 7 or the inner and outer wall 1, 2 is exposed to an interior pressure of a certain level, via the pressure line 16 (see FIG. 3) using the pressurized fluid, so that this area undergoes plastic expansion or broadening towards the flow cavity 17. The meandering structure generated by means of the above-mentioned welding process is broadened or opened towards the flow cavity 17, so that a cooling fluid can flow through, between the two heat conducting plates 7 or the inner and outer wall 1, 2 as well as between the welding locations 3, 3 a in a meandering pattern.

The manufacturing by means of bores and fixing screws is advantageous for small piece numbers or for the manufacture of a functional sample. In series manufacture, on the other hand, holding-down devices would be more practical. In that case, the above-mentioned bores within the circular welds can also be omitted. On the other hand, the bores may be maintained with correspondingly smaller diameter for a better penetration of the impregnating resin.

By means of the fixing screws 12, the cooling jacket is secured to the deformation core 13 in such a way that, during the internal high-pressure deformation, the inner heat conducting plate 7 cannot yield through the inner wall 1 (not visible in FIGS. 3 and 4) or the corresponding interior heat conducting plate, and it obtains, on its exterior side which is oriented towards the deflection core 13, a largely smooth exterior surface for a close fitting or tight contact with the object 19 to be cooled. In contrast, the wave structure with recesses 4, 4 a—which wave structure was already explained in reference to FIG. 1—on the outer casing in the area of the welding locations 3, 3 a and also of the fixing bores/screw 11, 12, and with the elevations 5, 5 a in between, is already imprinted in the outer wall 2 according to FIG. 4. Alternatively or additionally to the fixing bores 11 with fixing screws 12, it is advantageous to use support means, for example, in the form of holding-down devices, which in themselves are known in the deformation technique, to brace the outer casing of the outer wall 2, in each case with spatial delimitation, on the area of the welding locations 3, 3 a and optionally also of the welding sections 10 and/or the peripheral welding seam, in a controlled way during the inflation in the interior of the cooling jacket. Here, in the case of the outer wall 2, a structure can be imprinted which presents a slightly curved or wave-like structure, while the exterior side of the inner wall 1, which is oriented towards the interior in the direction of the object to be cooled, remains smooth because of the application on the deformation core 13 with its smooth outer casing. As a result, a particularly good heat transfer is achieved between the exterior side of the object to be cooled, for example, the surface of an electromotor, and the interior jacket of the cooling jacket. It is particularly advantageous if the holding-down devices or other protection means are oriented in such a way that the cooling jacket is applied by pressing with its inner wall 1 as perpendicularly as possible or directly on the surface of the deformation core.

In an additional manufacturing step according to FIG. 5, the cooling jacket so produced is provided with inlet and outlet means 18, for example, connectors, which are welded preferably directly on the outer wall 2 in the area of connection bores of the cooling jacket which pass through the outer wall 2. This occurs advantageously in an edge and/or corner area of the cylindrically bent cooling jacket plate sandwich. The transverse edges 14 of the latter, which during the bending almost abut against each other, and which are located opposite in proximity (see also FIG. 2), are held against each other, in order to clamp the cooling jacket around the stator 19 using elastic clamping means (not shown), such as, for example, spring clamps or the like.

According to FIG. 6, in the case of a cylindrical cooling jacket which is designed according to a second variant of the invention, not only the outer wall 2 is provided with recesses 4, 4 a and elevations 5, 5 a which alternate in the peripheral direction, the inner wall 1 is also configured with recesses 44, 44 a and elevations 55, 55 a which alternate in the peripheral direction. This structure which is wavy on both sides of the cooling jacket extends approximately symmetrically to an imaginary middle or connection line M in the flow cavity 17, for the individual welding locations 3, 3 a, by means of which the inner and outer wall 1, 2 of the cooling jacket are fastened to each other. The recesses 4, 4 a, 44, 44 a, which are delimited by adjacent elevations 5, 5 a, 55, 55 a (in that regard similarly to the embodiment example according to FIG. 1) originate from the individual welding locations 3, 3 a. In a deviation from the variant of the invention according to FIGS. 1-5, in FIG. 6, the flow cavity 17 is pressed on with its pillow- or meander-like structure by inflation and internal high-pressure deformation between an exterior cover jacket 22 and the interior object to be cooled, for example, the stator 19 of an electromotor, and broadened. As a result, analogously to FIG. 1, flow paths form in each case between individual welding locations 3, 3 a. During the application by pressing, a close fitting contact is established between the inner wall elevations 55, 55 a of the inner wall 1 of the cooling jacket, and the outer casing of the object to be cooled, for example, the rotor 19. Similar statements apply to the recesses 5, 5 a of the outer casing 2, where the latter is applied via the recesses from the interior against the cylindrical cover jacket 22. In the process of the internal high-pressure deformation of the inner and outer walls 1, 2 of the cooling jacket, between the cover jacket 22 and, for example, the rotor 19, which walls are fastened to each other via the welding locations 3, 3 a, an elastic and/or elastic-plastic deformation of the cover jacket 22 also occurs, followed by the cover jacket reacting, with the exertion of an inward directed radial counter pressure on the cooling jacket or its outer wall 2. As a result, the cooling jacket is pressed correspondingly more firmly on the object to be cooled, for example the stator 19. The elastic-plastic deformation of the cover jacket 22 manifests itself also on its exterior surface with alternating recesses 224 and elevations 225, which are approximately congruent to the recesses 4, 4 a and elevations 5, 5 a of the outer casing of the cooling jacket.

LIST OF REFERENCE NUMERALS

-   1 Inner wall -   2 Outer wall -   3, 3 a Welding locations -   4, 4 a, 44, 44 a Recess -   5, 5 a, 55, 55 a Elevation -   6 Passage -   7 Heat conducting plate -   8 Edges, four lateral edges -   8 a Facing edge -   I-v Rows or alignment -   9 Transverse alignment -   10 Longitudinal welding section -   11 Fixing bore -   12 Fixing screw -   13 Deformation core -   14 Transverse edge -   15 Mounting welding locations -   16 Pressure line -   17 Flow cavity -   18 Inlet and outlet means -   19 Stator -   20 Stator winding -   21 Joint -   22 Cover jacket -   224 Cover jacket recess -   225 Cover jacket elevation -   M Middle line 

1. Cooling jacket or heat exchanger to be placed in contact with solid products to be cooled, including electrical machines with a rotor which rotates inside or outside a stator (19), or with reactors or containers, the cooling jacket or heat exchanger having an inner and outer wall (1, 2) which between themselves delimit a flow cavity (17) which is provided with inlet and outlet means (18) for a coolant, and conducting means for the formation or delimitation of at least one flow path for the coolant between the inner and outer wall (1, 2) from the inlet means to the outlet means (18), where mutually facing individual flat places or flat sections of the inner and outer wall (1, 2) contact each other within their edges, and passages (6) for the coolant remain between the contacting flat places or flat sections, and one or more elevations (5, 5 a) and recesses (4, 4 a) alternate on one or more external sides or an outer casing of the inner or outer wall (2), characterized by the mutually contacting flat places or flat sections being permanently connected via individual joints (3, 3 a) or longitudinal joint sections (10).
 2. Cooling jacket according to claim 1, characterized by the elevations (5, 5 a) and the recesses (4, 4 a) presenting a convex curvature and a concave curvature respectively.
 3. Cooling jacket or heat exchanger according to claim 2, characterized by the joints (3, 3 a) or joint sections (10) being implemented by fastening by welding, soldering, gluing, folding, clinching, screwing or riveting.
 4. Cooling jacket or heat exchanger according to claim 3, characterized by the joints (3, 3 a) or joint sections (10) being arranged in the area of the recesses (4, 4 a) of an external side of the inner or outer wall (2).
 5. Cooling jacket or heat exchanger according to claim 4, characterized by the recesses (2) or flow conducting means being implemented with the joints (3, 3 a) or joint sections (10).
 6. Cooling jacket or heat exchanger according to claim 5, with a cylindrical or elongated or rotation symmetrical base form, characterized by—when viewed in a parallel alignment (9) or along a cylinder, longitudinal or symmetry axis—on the external surface or side of the inner or outer wall (2), elevations (5, 5 a) alternating with recesses (4, 4 a), where each elevation (5, 5 a) or recess (4, 4 a) is delimited on all sides in each case by recesses (4, 4 a) or elevations (5, 5 a) which are located outside of the alignment (9).
 7. Cooling jacket or heat exchanger according to claim 6, characterized by the flow conducting means being implemented with the joints (3, 3 a) or joint sections (10) or connection or sections between the inner and outer wall (1, 2).
 8. Cooling jacket or heat exchanger according to claim 7, characterized by an arrangement of the joints (3, 3 a) or joint sections (10) such that the flow paths of the coolant have a meandering course or turbulent course.
 9. Cooling jacket or heat exchanger according to claim 8, characterized by, in a circumferential direction (I-V) about the cylinder, longitudinal or symmetry axis, several longitudinal joint sections (10) of the inner and outer wall (1, 2) being offset alternately toward one edge (8) and to a facing edge (8 a).
 10. Cooling jacket or heat exchanger according to claim 9, characterized by, in a circumferential direction (I-V) about the cylinder, longitudinal or symmetry axis or in a direction (9) parallel to the cylinder, longitudinal or symmetric axis, several joints (3, 3 a) or joint sections (10) are arranged with mutual offset.
 11. Cooling jacket or heat exchanger according to claim 10, characterized by the joints (3, 3 a) or joint sections (10) being arranged with regular structure or equal separations between each other.
 12. Cooling jacket or heat exchanger according to claim 11, characterized by mounting or fixation means (11, 12) on or in the outer or inner wall (2, 1) for attachment to a deformation device (13).
 13. Cooling jacket or heat exchanger according to claim 12, characterized by the inner or outer walls (1, 2) being implemented with plate parts having a thickness in the range of 0.3-2.00 mm.
 14. Cooling jacket or heat exchanger according to claim 13, with a hollow cylindrical base form where the cylinder peripheral material presents an axis-parallel butt seam or joint (21), which is formed by edges (14) of the inner and outer wall (1, 2), which edges face each other in the circumferential direction (I-V), characterized by the facing edges (14) being held together or immediately opposite each other by spring clamps, claw springs or other elastic clamping means or welding locations (15).
 15. Cooling jacket or heat exchanger according to claim 14, characterized by the outer or inner wall (1) being formed with a smooth exterior side to achieve a close fitting contact with the solid product.
 16. Cooling jacket or heat exchanger according to claim 1, characterized by both the inner wall (1) and also the outer wall (2), on their respective exterior sides, being formed with several alternating elevations (5, 5 a; 55, 55 a) and recesses (4, 4 a; 44, 44 a).
 17. Cooling jacket or heat exchanger according to claim 16, characterized by the alternating elevations (5, 5 a; 55, 55 a) and recesses (4, 4 a; 44, 44 a) extending symmetrically with respect to a middle line of the flow cavity, which middle line connects the joints (3, 3 a) or joint sections (10).
 18. Cooling jacket or heat exchanger according to claim 17, characterized by the cooling jacket or heat exchanger being enclosed or enveloped by a cover jacket (22).
 19. Cooling jacket or heat exchanger according to claim 18, characterized by the cover jacket (22) having a greater wall thickness than that of the inner or outer wall (1, 2) of the cooling jacket or heat exchanger.
 20. Cooling jacket or heat exchanger according to claim 19, characterized by a structural integration with the cover jacket (22), like a shrink wrap.
 21. Cooling jacket or heat exchanger according to claim 20, characterized by the inlet and outlet means (18) for coolant extending by protrusion through the passages formed in the wall of the cover jacket (22).
 22. Method for the manufacture of a cooling jacket or heat exchanger with an internal and an outer wall (1, 2) and a flow path in between for coolant, the method comprising: a) forming a solid composite from two individual heat conducting plates (7) as inner and outer walls (1, 2), by connecting them permanently, one against the other, by their edges and within said edges via individual joints (3, 3 a) or one or more longitudinal joint sections (10) b) after step a) forming a flow cavity (17) by internal high-pressure deformation between the inner and outer walls (1, 2) c) after step a) or b), attaching an inlet or outlet (18) for cooling fluid, which leads to the flow cavity (17) within the composite.
 23. Method according to claim 22, characterized by, for the formation of the solid composite, the two heat conducting plates (7) being placed one on top of the other, in a flat state, and welded or otherwise connected at their edges (14).
 24. Method according to claim 22, characterized by, for the formation of the solid composite, individual joints (3, 3 a) or joint sections (10) being formed through its external side(s) or its outer casing, whereby facing inner sides of the inner or outer wall (1, 2) are connected to each other.
 25. Method according to claim 24, characterized by the application of the individual joints (3, 3 a) or joint sections (10) being achieved by welding through the inner or outer wall (1, 2).
 26. Method according to claim 25, characterized by the joint places (3, 3 a) or sections (10) being are produced by point, circular or line welding on the exterior side of the inner or outer wall (1, 2).
 27. Method according to claim 26, characterized by the solid composite being adapted by deformation to the external contour(s) of a product (19) to be cooled, to apply the cooling jacket or heat exchanger with the exterior side of its outer or inner wall (1) with as close fitting a contact as possible to the product (19).
 28. Method according to claim 27, characterized by, for the deformation, the still flat plate composite (1, 2; 7) is plastically deformed by means of a deformation device (13) or by means of a support body whose external contour corresponds to that of the product (19) to be cooled.
 29. Method according to claim 28, characterized by, for the deformation, the still flat plate composite (1, 2; 7) is bent to a cylindrical shape about a deformation core (13) or a support body, and connected to edges (14) which are located opposite or abut against each other.
 30. Method according to claim 29, characterized by holding the plate composite (1, 2; 7) with the exterior side of its outer or inner wall (1) by means of fixation means (11, 12) in contact with the deformation device (13) or the support body.
 31. Method according to claim 30 30, characterized by pressing the plate composite (1, 2; 7) for its fixation in the area of the welding or other joints (3, 3 a) on the support body or the deformation device (13).
 32. Method according to claim 31, characterized by the plate composite being pressed on the support body or deformation device before step b).
 33. Method according to claim 32, characterized by the internal high-pressure deformation being carried out by introducing a fluid pressure medium between the inner and outer wall (1, 2).
 34. Method according to claim 33, using a deformation device (13) for the deformation the solid plate composite (1, 2; 7), where, for the formation of the solid composite, individual joints (3, 3 a) or joint sections (10) are applied over its external side(s) or its outer casing, which results in the mutual connection of facing internal sides or interior flat places of the inner or outer wall (1, 2), characterized by, during the phase of internal high-pressure deformation, positioning holding-down devices in contact with the external side(s) or the outer casing of the outer wall (2) in the area of the joints (3, 3 a) or joint sections (10) or in the area of a peripheral seam or of a welded peripheral edge, to hold the composite (1, 2; 7) with the exterior side of its outer or inner wall (1) in contact with the deformation device (13).
 35. Method according to claim 34, characterized by coating the external side of the outer or inner wall (1) with a coating made of a coating substance that improves the heat transfer.
 36. Method according to claim 36, where the cooling jacket or heat exchanger is used for a stator (19) of an electric machine without casing, which stator is impregnated with casting or impregnation resin, characterized by moving the inner wall (1) of the deformed plate composite (1, 2; 7) into contact with the stator (19), for as long as the casting or impregnation resin has not yet hardened completely.
 37. Method according to claim 36, characterized by impregnating the stator (19), in the area of its external margin or external periphery, with casting or impregnation resin.
 38. Method according to claim 37, characterized by, before the impregnation, mounting the cooling jacket on a solid product to be cooled.
 39. Cooling arrangement with an electric machine or with a reactor or container, having a jacket or enclosure of the electric machine or its stator (19), the reactor or the container, with an inner wall (1) of a cooling jacket or a heat exchanger, the cooling jacket or heat exchanger having an inner and outer wall (1, 2) which between themselves delimit a flow cavity (17) which is provided with inlet means and outlet means (18) for a coolant, and conducting means for the formation or delimitation of at least one flow path for the coolant between the inner and outer wall (1, 2) from the inlet means to the outlet means (18), where mutually facing individual flat places or flat sections of the inner and outer walls (1, 2) contact each other within their edges, and passages (6) for the coolant remain between the contacting flat places or flat sections, and one or more elevations (5, 5 a) and recesses (4, 4 a) alternate on one or more external sides or an outer casing of the inner or outer wall (2), characterized by the mutually contacting flat places or flat sections being permanently connected via individual joints (3, 3 a) or longitudinal joint sections (10).
 40. Cooling arrangement according to claim 39, characterized by protruding elevations (55, 55 a) formed on the inner wall (1) of the cooling jacket and only the inner wall (1) of the cooling jacket being in a heat transferring contact via its protruding elevations (55, 55 a) with an outer casing or an outer wall of the stator (19).
 41. Arrangement according to claim 40, characterized by a coating with plastically deformable heat conducting means between the external side of the inner wall (1) and the external contour of the stator.
 42. Arrangement according to claim 41, where stator windings (20) of the electrical machine are cast or impregnated with a casting or impregnation compound, characterized by the casting or impregnation compound being also located between the exterior side or the concave outer casing of the inner wall (1), and the outer casing of the stator (19) or stator casing. 